FIG. 1 is a circuit diagram illustrating an exemplary circuit for a conventional switching regulator as described in Japanese Patent Application JP 2007-004995, for example. In FIG. 1, the switching regulator includes a voltage control operational amplifier and a current control operational amplifier, and the output current is detected based on a voltage difference Vd caused by a current flowing in a current detection resistor for generation of a constant current.
In conventional switching regulators, resistors are used to detect output currents, which may cause loss due to currents flowing in the resistors. Then, if resistances of the resistors are set to be smaller for reduction in the loss, higher-precision operational amplifiers must be used in the switching regulators.